Combustion Chamber Inserts; Valve Springs; Valve Guides - Perkins 4.108 Workshop Manual

CYLINDER HEAD-E.4
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COMBUSTION CHAMBER INSERTS
These can be gently tapped out of their locations by
means of a short length of curved bar through the
atomiser bore. When refitting they must be located by
means of expansion washers in the recesses provided,
as shown in Figs. E.8 and E.g.
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Cleaning
Remove any carbon from the cylinder head.
If the water jacket within the cylinder head shows
signs of excessive scale, then a proprietary brand of
descaling solution may be used, if possible the
cylinder head should be tested for water leakage after
such treatment at the pressure given on Page B.7.
VALVE SPRINGS
It is advisable to fit new valve springs whenever the
engine undergoes a major overhaul. Where a top over-
haul only is being carried out the springs should be
examined, paying particular attention to squareness of
ends and pressures developed at specific lengths, the
details of which can be found on Page B.8.
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VALVE GUIDES
The worn guides should be removed either by means
of a press and a suitable "dolly" or the valve guide
removal tool shown in Fig. E.10.
Before fitting the new guides remove any burrs from
the cylinder head parent bores, then smear the bores
with clean oil and either press in the new guides or
pull them in by means of the tool shown in Fig. E.11,
until the guide protrusion above the head top face is
that quoted on Page B.7.
NOTE: Special care should be exercised during this
operation as the guides, being made of cast iron, are
therefore comparatively brittle.
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